Design engineers are often faced with the dilemma of material selection. Frequently, material that would work the best for one specific element of the design is lacking in properties required by other elements of the design. For example, a material may exhibit good corrosive resistance, electrical conductivity, or thermal conductivity, yet be lacking in the strength, hardness, weldability, or wear resistance required by the final design.
PA&E’s Bonded Metals Division, formerly known as Northwest Technical Industries (NTI), performs explosive metal bonding — a process that allows design engineers to place a certain material exactly where they need it in the design, without compromising other critical design elements.
Applications for Explosively Bonded Metals
Explosively bonded metals can be used as weldable transitions between two dissimilar metals. For example, an explosively bonded strip of aluminum and stainless steel can be inserted between an aluminum structure and a stainless steel structure. This allows for direct conventional welding of the stainless steel structure to the stainless steel side of the bi-metallic strip, and then direct conventional welding of the aluminum structure to the aluminum side of the bi-metallic strip. The resulting joint is a fully-welded, aluminum-to-stainless steel structure. This application allows designers and fabricators to apply specific materials to the location or function that they are best suited for without having to make the entire structure out of one of the metals, thereby limiting the design’s potential. The most common application of this technique is to directly weld high-strength, stainless steel action parts onto aluminum structures.
Precious Metal Conservation
Precious metals, refractory metals, and other expensive alloys can be explosively bonded, in thin layers, to the specific area of the designed part. This not only significantly reduces the cost of the manufactured part or material, but allows for the use of more structurally sound materials to be used where required.
Galvanic Corrosion Elimination
Explosively bonded dissimilar metals are a significant inhibitor to galvanic activity that would occur between mechanically fastened dissimilar metals. Maritime applications benefit from the use of explosively bonded metals by allowing for weldable transitions between dissimilar metals that also reduce or eliminate galvanic corrosion.
Corrosive Resistant Linings
The most common application of explosively bonded (or clad) metals, is as corrosive or erosive resistant linings of pressure vessels, chemical process tanks, heat exchangers, and tube sheets. Not only do users benefit from the corrosive lining, but also from significant cost reduction by being afforded the opportunity to utilize structural steels to improve wall strength without having to manufacture the entire structure out of the, typically expensive, corrosive resistant materials.
Similar to corrosive lining, bearing materials can be explosively bonded to sheets of metal. This allows for a structurally sound component to have a bearing surface clad directly to it, significantly reducing the wear of the part and improving its operation.
Thin layers of shielding materials can be bonded to other structural metals or components. This has been a cost-effective method of providing radiation shielding to satellites.
Pacific Marine & Industrial is an authorized distributor of PA&E bonded metal products.